How to find the molar mass of the weak acid

It took 40.23 mL of 0.5065 M sodium hydroxide to react completely with 3.210 g of a weak acid HA. find the molar mass of the weak acid?

(0.5065 mol/L) (0.04023 L) = 0.020376495 mol of NaOH

NaOH reacts with HA in a 1:1 molar ratio. This means 0.020376495 mol of HA was present.

3.210 g / 0.020376495 mol = 157.5 g/mol (to four sig figs)